The present invention relates to integrated circuits and more particularly to packaging multiple substrate technologies within a housing.
Integrated circuits requiring a particular substrate technology, i.e. printed circuit boards, typically have manufacturing and assembly requirements that differ dramatically. For example, a thick film ceramic substrate is significantly different from a printed circuit board, making it difficult to combine the use of these two very different substrate technologies into a single, convenient, and cost effective package. Furthermore, certain unpackaged die and flip-chip technologies, called hybrid circuits, also have substrate technologies that differ from one another.
Many applications such as engine controller applications often require the integration of many different substrate technologies into a single application. For example, electronics associated with controlling an engine have sensitive micro-electronics requiring assembly to a printed circuit board that typically occurs within a clean room, be integrated with more durable devices, such as output driver circuits that are implemented with flip-chips on thick film ceramic substrates. The latter requiring a heat sink for heat removal from the power dissipating circuitry
It is typical for integrated circuit applications to have strict space and weight constraints that make packaging an important factor in the overall system design. Often, the integration of different types of circuitry results in redundant integrated circuit and driver packaging, which increases overall circuit density and uses up valuable packaging space. The disadvantages include increased complexity, high cost, and an increase in the risk of poor reliability.
There is a need for a packaging strategy that enables interconnection of different substrate material technologies without the disadvantages associated with the prior art.
It is an object of the present invention to provide a strategy for partitioned packaging of multiple substrates in a single, enclosed housing. It is another object of the present invention to integrate multiple circuits having different substrate technologies into a single housing. Yet another object of the present invention is to include a heat sink in the partitioned housing. A further object of the present invention is to eliminate the need for redundant integrated circuit packaging.
The present invention provides a partitioned packaging strategy that enables interconnection of different substrate technologies into a single housing. The housing assembly utilizes vertical space for packaging. A heat sink is provided for removal of heat. At the same time, sensitive electronics can be fully enclosed and isolated from other more durable electronics, thereby eliminating the need to fully assemble the integrated circuit in an expensive clean room environment.
According to the present invention there is provided a housing, preferably cast aluminum, having a cavity in one or more facing sides. Hybrid circuits, and specifically ceramic-based hybrid circuits, are housed in the cavities. A bottom portion seals the housing and has a row of pins provided for interconnecting the circuits housed in the separate cavities, thereby allowing the integration of different types of circuits in a single, fully enclosed, yet partitioned, housing. Further, the housing itself can be connected to another device such as a printed circuit board. Thereby providing interconnection between the hybrid assemblies within the housing and other external devices.
In one embodiment of the present invention, a high temperature plastic is used for the housing cover, and cast aluminum is used for providing heat sink properties. The heat sink may further be mechanically mounted to a printed wiring board and to the housing, thereby completing a thermal path for drawing heat away from the circuitry.
In yet another embodiment of the present invention, a cover may enclose the entire housing, or portions thereof, to isolate and protect sensitive circuits from the surrounding environment. This provides the advantage of sealing and testing the assembly for subsequent shipping to a remote site, where the housing can be integrated into the product being assembled in a less controlled assembly environment.
Other objects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.